A wide variety of ice makers have been developed in the prior art. These ranged from the early, large ice making apparatus that made 300 pound blocks in salt water brine at sub-freezing temperature to present day automatic ice makers that make small ice cubes contiguous tubes, plates and the like then through suitable thawing means dump the resultant cubes into a bin, or storage receptacle. While any of a number of products may be prepared in desired shapes such as edible bars and frozen confections, the most frequently employed apparatus of this type is that for producing ice cubes for restaurants, motels and the like.
There are numerous patents in this area which serve to delineate the consistent progress that has been made in improving this type of apparatus. The most pertinent patent of which I am aware is U.S. Pat. No. 3,430,452. As delineated therein, the National Sanitation Foundation is formulating standards of cleanliness relating to automatic frozen food products and the apparatus and methods for making them. In conforming with such standards, one of the primary objects of this invention is to provide apparatus and method for making the ice cubes to conform with the standards for cleanliness and the like.
One of the defects of the prior art is that the apparatus is not readily dumped unless it has an external sheet frozen to the respective cubes. When the external sheet is frozen, controlling its thickness is difficult and requires expensive, complex, difficulty maintainable controls in order to allow the cubes to separate easily. Otherwise, the sheet ice that forms over the top of the cubes is difficulty broken up into individual cubes instead of sheets of cubes.
Another problem has been detection of an adequate quantity of cubes within a bin and interrupting the icemaking process until some of the ice has been used. In the past this has required complex controls such as "electric eye" type of light and light sensing apparatus, feelers, or the like. Another approach has been the use of a thermal switch. These switches and related temperature--responsive capsules and capillaries require very close adjustments and are susceptible to false indications, such as changes in ambient temperature.